Nuclear energy originates with a nuclear reaction within a “nuclear reactor”. A nuclear reactor typically includes a vessel defining a chamber and a core including internal components situated within the chamber. In commercial power reactors, for example, the core includes a plurality of internal components arranged to accommodate the fuel assemblies and measurement devices/probes. The nuclear reaction releases energy, transferring heat to a circulating fluid.
The nuclear reactor core is the location where the chain reaction of nuclear fission occurs and generates energy. Nuclear fissions also induce irradiation of the nuclear reactor core components and thus generate various irradiated materials. For example, the inside of the vessel, as well as the reactor internal components, are considered irradiated. To comply with pertaining regulations for dismantling and decommissioning a nuclear reactor at the end of its operating life, the irradiated materials require certain procedures/processes for handling.
Removal and disposal of a nuclear reactor's fuel core is not considered part of the decommissioning process because used nuclear fuel disposal is subject to a different process. However, the decommissioning of the remaining portions the nuclear reactor core, for example, the vessel and the reactor internal components, are described in the present application.
Many nuclear power plants will be shut down in the coming future, whether such shutdowns are scheduled or premature. Therefore, there exists a need for a process with improved efficiency and safety for decommissioning a nuclear reactor vessel and internal components.